The overall aim of this research project is to contribute to the development of a comprehensive theory of speech perception within the framework of human information processing theory and methodology. The specific objectives have focused on the "stages" of perceptual analysis and the types of operations that occur at each of these processing stages. Goals for the current year are: 1) to continue the theoretical development of an information processing model of speech sound perception; 2) to study and provide an explanatory account of selective adaptation of synthetic stop consonants; 3) to develop a computer simulation model of selective adaptation; 4) to study the identification and discrimination of nonspeech signals having temporal properties similar to speech; 5) to test the Quantal Theory of Speech within the context of vowel mimicry paradigm; 6) to assess the effects of discrimination training on the identification and discrimination of rapid spectrum changes; 7) to begin a program of research on the perception of speech and nonspeech signals by pre-linguistic infants; and 8) to continue development of the hardware and software facilities of our on-line computer-controlled laboratory. BIBLIOGRAPHIC REFERENCES: Cutting, J.E. and Pisoni, D.B. An information processing approach to speech perception. In J.F. Kavanagh and W. Strange (Eds.) Implications of basic speech and language research to the school and clinic. Cambridge: The M.I.T. Press, 1977 (In Press). Liberman, A.M. and Pisoni, D.B. Evidence for a special speech perception subsystem in the human. In T.H. Bullock (Ed.) Recognition of complex acoustic signals. Berlin: Dahlem Konferenzen, 1977 (In Press).